Conventionally, a controller for controlling an EPS (electric power steering) system mounted on a vehicle has a structure for fixing a vertical type connector so as to insert and remove the connector vertically with respect to a surface of a printed board. FIG. 1 shows an example of the structure. The vertical type connector 11 made of resin is fixed to a heat sink 12 made of metal with a screw 13. The heat sink 12 is fixed to a printed board 14 with another screw 15. The connector 11 includes a terminal 17, 18, which protrudes from an inner portion of the connector 11 toward an outside of the connector 11. The terminal 17, 18 has an elongated shape, and a power source voltage current and a signal flows through the terminal 17, 18. The terminal 17, 18 penetrates through a through hole of the printed board 14 so that an end of the terminal 17, 18 is bonded to the printed board 14 with a solder 19.
A collar 11a made of metal is embedded in a screw portion of the connector 11 so as to be screwed in a vertical direction of the connector 11. Thus, the metal collar 11a is embedded in the resin connector 11. The collar 11a has a cylindrical shape. The screw 13 is engaged (i.e., screwed) with the collar 11a so that the connector 11 is fixed to the heat sink 12. Thus, the collar 11a is used for the screw portion because the resin connector 11 may expand and contract so that the screw 13 looses and the connector 11 is removed from the heat sink 12 if the screw 13 is directly engaged with the resin connector 11.
The above connector structure is described in JP-A-H08-17494.
However, in the above connector structure, since a thermal expansion coefficient of the connector 11 is different from the printed board 14, a degree of expansion and contraction in the connector 11 is different from the printed board 14. Thus, a stress generates between the connector 11 and the printed board 14. The stress is applied to the terminal 17, 18 so that the solder portion of the terminal 17, 18 is damaged. Thus, the terminal 17, 18 may be disconnected to the printed board 14. To protect the solder portion, a length of the terminal 17, 18 is increased so that expansion and contraction in the connector 11 and the printed board 14 are absorbed. In view of assembling performance between the terminal 17, 18 and the printed board 14, a distance G1 between the heat sink 12 and the printed board 14 is reduced.
Further, since the collar 11a is embedded in the resin connector 11 so as to fix the connector 11 on the heat sink 12, a manufacturing cost of the connector 11 increases.